no, michael wittman was NOT killed by a Typhoon; although is true that it was believed to be the reason for some time.
One of the best studies on Wittmann's death I've read so far is this one:
Until 1983, the destruction of Wittmann's Tiger was an mystery even for crews of sSSPzAbt 101. Many sources say that it was destroyed by the "Firefly Ambush", but different units claimed to ambush and destroy Wittmann's Tiger, including those of the either 1st Polish Armored Division, 4th Canadian Armored Division (Canadian Shermans supposedly surrounded and shot Wittmann's Tiger to pieces) or 33rd British Independent Armored Brigade. In the memoirs of a former member Mr.F.R of sSSPzAbt 101, official version at the time stated that Wittmann's Tiger was destroyed by an airplane bomb. Both presented a picture of Wittmann's Tiger without its turret with the gun barrel placed on the hull which in fact is the picture of SS-Untersturmführer Alfred Günther's Tiger destroyed by an airplane bomb at Evrecy. Along with those two versions, some claims were made that units, which were not even present in the area at the time, were responsible for destroying Wittmann's Tiger. In 1945, Mr.Serge Varin found Tiger #007. Mr.Varin was interested in this tank because its turret was teared away from the hull. Mr.Varin examined Wittmann's Tiger and noticed that it was not penetrated by any shells fired at it during the fighting. The only damage to the hull was a big hole in the rear, near the engine deck.
After further examination Mr.Varin concluded that the impact came from the air. The rocket hit Tiger's rear deck (made of 25mm thick armor), penetrated the air intakes and exploded causing the explosion in the engine compartment and fighting compartment which ignited the stored ammunition. The second explosion instantly killed the entire crew and blew off the turret into the air. According to Varin, Wittmann's Tiger was destroyed by a rocket fired from a Royal Air Force Hawker "Typhoon" MkIB - attack aircraft. Typhoons were armed with HE (High-explosive) rockets and took heavy tow of German tanks during the Normandy battles (for example on August 8th of 1944, Typhoons destroyed 135 German tanks and among those Tiger #007).
Finally, it was proven that Wittmann's Tiger was destroyed by fire from tanks of "A" Squadron of Northamptonshire Yeomanry. British Firefly crew observed advancing Tigers and opened fire at when Tigers were some 800m away. According to original War Diary of "A" Squadron, at 12:20, 3 Tigers were moving towards the Squadron and were destroyed at 12:40, 12:47 and 12:52 without any losses. After the first Tiger was destroyed at 12:40, second one returned fire but was hit and blew up in a loud explosion. Following that, third Tiger was knocked out after receiving two hits. Wittmann's Tiger was destroyed as second at 12:47 by British Sherman VC "Firefly", armed with 17 pounder gun capable of penetrating Tiger's armor at range of 800m. The force of explosion blew off the turret, which landed upside down away from the hull. Wittmann did not know that British had Firefly in the area and felt confident in attacking their position with his Tigers, otherwise he would take different approach to the whole attack. After Wittmann failed to return from the battle, search for him by the members of the 12th SS Panzer Division "Hitlerjugend" and his battalion took place during the day and on the night of 8/9th.
Michael Wittmann and his crew was killed in action on August 8th of 1944, at Gaumesnil near Cintheaux and were buried in an unmarked grave. In March of 1983, the unmarked field grave of Tiger #007's crew was discovered during the construction of the road and was excavated. It was possible to identify the remains by Wittmann's dental records and Heinrich Reimers's (driver) identification tag. Wittmann and his crew was then officially buried in the German Military Cemetery of "De La Cambe" in Normandy, France. The cemetery is located on the National Road 13 (RN 13) between Isigny-sur-Mer and Bayeux. Michael Wittmann is buried in square 47, row 3, grave 120 of "De La Cambe". On August 8th of 1944, crew of Tiger #007 from 2nd Kompanie of schwere SS-Panzer Abteilungen 101 of LSSAH was as follows:
SS-Sturmmann Rudolf "Rudi" Hirschel (radioman) 24/1/3 - 44/8/8 (20 years old),
SS-Unterscharführer Henrich Reimers (driver) 24/5/11 - 44/8/8 (20 years old),
SS-Unterscharführer Karl Wagner (observer) 20/5/31 - 44/8/8 (24 years old),
SS-Sturmmann Günther Weber (loader) 24/12/21 - 44/8/8 (20 years old),
SS-Haupsturmfuhrer Michael Wittmann (commander) 14/4/22 - 44/8/8 (30 years old).
He ended up his career as a Commander of 2.Kompanie schwere SS-Panzer Abteilung 101 (part of 1st SS Panzer Division "LSSAH").SS-Haupsturmfuhrer Michael Wittmann was the most successful tanker ace of World War II. His friends said that Michael Wittmann was quiet man even during combat and that he had 6th sense, to know where and how to engage the enemy. Wittmann commanded excellent crews, who were able to fully cooperate withhim and anticipated his orders.
Wittmann was highly admired by his comrades and very highly thought of by his superiors. Michael Wittmann represents a real hero who fought to the bitter end for his Fatherland. Wittmann's personal bravery is unquestionable and his place in the annals of military history thoroughly deserved
Wittmann's tiger was destroyed by a British (not canadian) Firefly, and not by a tyhoon. In fact Typhoon's capabilities as armor destroyer are/were extremely overrated.
Source is "atchungpanzer.com". This info can be found and read at
http://www.achtungpanzer.com/gen3.htm